Goodwill and Intangible Assets (Details Textuals) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($) acquisition	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill, Impairment Loss		$ 0	$ 0
Goodwill acquired during period	$ 3,000
Goodwill		971,951	$ 968,844
Finite-Lived Core Deposits, Gross		15,000
Number of Acquisitions | acquisition	2
Corporate and Commercial Specialty | Operating Segments
Business Acquisition [Line Items]
Goodwill		$ 428,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Additions to finite-lived intangible assets	$ 1,000